This invention relates to a hose reinforcing filament cord, a production method thereof, and the hose produced by the method.
In more detail, the invention relates to a hose reinforcing multiple filament cord and to a substantially trouble-free hose production process. It further relates to a reinforcing cord that has both excellent flexibility and adhesiveness to rubber compounds in the hose, such as halogenated butyl rubber or ethylene-xcex1-olefin-nonconjugated diene copolymer rubber compositions (hereinafter called xe2x80x9cEPDM rubberxe2x80x9d). The invention further relates to the hose produced.
Polyester filament yarns such as polyethylene terephthalate filament yarns have useful physical properties for reinforcing hoses. They have high tenacity and modulus, small elongation and creep and excellent fatigue resistance. They have been used for incorporation into rubber hose reinforcing filament cords.
However, polyester filament yarns suffer from the problem of having poor adhesiveness to rubber, since they are inactive on rubber surfaces.
For example, hoses used for automobile air conditioners in recent years generally consist of an innermost layer made of a polyamide resin in contact with a refrigerant gas, a layer formed of gas-impermeable halogenated butyl rubber such as chlorinated butyl rubber around the innermost layer, a further reinforcing layer formed of reinforcing filament cords of polyester filament yarns having an adhesive composition film disposed around its surface and in contact with the halogenated butyl rubber layer, and another layer formed of a halogenated butyl rubber or EPDM rubber around the cord layer. Various techniques have been developed to improve the adhesiveness between the polyester filament cords and the halogenated butyl rubber or EPDM rubber layers in this hose, without success.
To complicate the matter, when plural adhesive-treated filament cords are mechanically paralleled and braided, or paralleled and spiraled, as is often desirable in hose construction, the filament cords cannot be accurately paralleled due to frictional resistance that exists between the adhesive-treated filament cords, or due to friction with associated guides, to deform the hose, or to cause deposition waste material from various treating agents to adhere or be scattered in the vicinity, thus lowering productivity and polluting the working environment. Furthermore, when the filament cords are used for hose for reinforcing brakes, or for hose for carrying a refrigerant gas, the filament cords are required to have good flexibility and resistance, and to attain good hose installation convenience, vibration absorbability, and other beneficial properties not heretofore attainable.
Japanese Patent Laid-Open (Kokai) No. 62-276083 describes a method for treating a rubber reinforcing polyester filament yarn, by treating a polyester filament yarn with a treating agent containing a cresol novolak type polyepoxide and water soluble nylon, successively treating with a treating agent containing a polyepoxide compound, blocked isocyanate and rubber latex, and then treating with a mixture consisting of resorcin, formaldehyde, rubber latex, ethyleneurea and cresol novolak type polyepoxide. However, when such filament cords are applied to a hose, their adhesiveness to EPDM rubber or halogenated butyl rubber is inadequate.
Japanese Patent Laid-Open (Kokai) No. 63-92776 describes treating a polyester filament yarn by a first treating agent containing an epoxy compound and treating by a second treating agent containing a mixture consisting of an initial condensation product of resorcin-formaldehyde and rubber latex, ethyleneurea compound, cresol novolak type polyepoxide and inorganic oxide. However, the resulting polyester filament yarn has problems. Its adhesiveness to halogenated butyl rubber is poor. Further, a large amount of dust is caused by the treating agents and is scattered during the hose production process, with detriment to the working environment.
Japanese Patent Laid-Open (Kokai) No. 10-81862 discloses a method for treating a polyester filament yarn using a treating agent obtained by mixing an initial condensation product of resorcin-formaldehyde, styrene-butadiene-vinylpyridine terpolymer latex, styrene-butadiene copolymer latex and cresol novolak type polyepoxide at a specific ratio.
Japanese Patent Laid-Open (Kokai) No. 61-19878 describes a filament cord treated by a mixture consisting of an initial condensation product of resorcin-formaldehyde, styrene-butadiene-vinylpyridine terpolymer latex, styrene-butadiene copolymer latex, parachlorophenol-resorcin-formaldehyde co-condensation product and dimethylsiloxane, to make the rubber reinforcing filament cord smooth.
However, it is difficult to secure the necessary adhesiveness even by these methods, and it is actually impossible to satisfy all of the combined properties of adhesiveness, flexibility, friction resistance in the hose production process, and still resolve the problem of deposition of waste from treating agents.
An object of the invention is to provide a rubber hose reinforcing polyester filament cord having excellent flexibility and adhesiveness to a halogenated butyl rubber compound or EPDM rubber compound, without causing difficulties such as deposit of waste from treating agents in the hose production process.
It is another object to provide a trouble-free production method for such a hose.
More specifically, another object of the invention is to provide a method for producing a rubber hose reinforcing polyester filament cord, which satisfies all of the requirements for flexibility of the filament cord, adhesiveness of the cord to a halogenated butyl rubber or to an EPDM rubber, and to provide smoothness of the filament cord, all without deposit of excessive waste from treating agents in the processing area.
The foregoing and other objects and advantages of this invention will further become apparent, and in the drawings.